Thermodynamic and Dynamic Responses to Deforestation in the Maritime Continent: A Modeling Study
Thermodynamic and Dynamic Responses to Deforestation in the Maritime Continent: A Modeling Study
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DOI：
10.1175/jcli-d-18-0310.1
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发表时间：
2019-06-01
影响因子：
4.9
通讯作者：
Chien, Rong-You
中科院分区：
文献类型：
--
作者：
Chen, Chu-Chun;Lo, Min-Hui;Chien, Rong-You
热带森林砍伐可导致当地地表能量和水收支发生重大变化，从而影响大气稳定性。这些影响可能反过来导致降水产量的变化。在过去的几十年里，海洋大陆（MC）经历了严重的森林砍伐，但与亚马逊和刚果雨林的森林砍伐相比，它受到的关注较少。本文采用全球（群落地球系统模式）和区域气候模式（4.6版区域气候模式）进行森林砍伐数值试验，探讨降水对MC森林砍伐的响应。结果表明，MC地区的森林砍伐导致了地表温度和局地降水的增加。大气水汽收支分析表明，降水增强与垂直水汽平流项动力分量的关系大于与热力分量的关系。湿润静态能垂直剖面的进一步分析表明，毁林地区的大气不稳定性增加是由于800-850 hPa附近的异常湿润和从地表延伸到750 hPa的异常增温。这种不稳定性有利于上升空气运动，从而加强低空水汽辐合。此外，与MC森林砍伐相关的垂直运动增加与拉尼娜事件产生的垂直运动增加相当。这些发现不仅提供了解释MC森林砍伐对当地气候响应的机制，而且还深入了解了气候模式在模拟降水响应方面存在分歧的可能原因。
Tropical deforestation can result in substantial changes in local surface energy and water budgets, and thus in atmospheric stability. These effects may in turn yield changes in precipitation. The Maritime Continent (MC) has undergone severe deforestation during the past few decades but it has received less attention than the deforestation in the Amazon and Congo rain forests. In this study, numerical deforestation experiments are conducted with global (i.e., Community Earth System Model) and regional climate models (i.e., Regional Climate Model version 4.6) to investigate precipitation responses to MC deforestation. The results show that the deforestation in the MC region leads to increases in both surface temperature and local precipitation. Atmospheric moisture budget analysis reveals that the enhanced precipitation is associated more with the dynamic component than with the thermodynamic component of the vertical moisture advection term. Further analyses on the vertical profile of moist static energy indicate that the atmospheric instability over the deforested areas is increased as a result of anomalous moistening at approximately 800-850 hPa and anomalous warming extending from the surface to 750 hPa. This instability favors ascending air motions, which enhance low-level moisture convergence. Moreover, the vertical motion increases associated with the MC deforestation are comparable to those generated by La Nina events. These findings offer not only mechanisms to explain the local climatic responses to MC deforestation but also insights into the possible reasons for disagreements among climate models in simulating the precipitation responses.